Long Arm kits, Pros, Cons, good the bad???

[Black1990jeep]

I am looking maybe into long arms. I have a 1990 XJ, 33x12.5 MT tires, 6 inch lift, Atlas II transfer case, center frame stiffeners, front D30 with locker, ford 9 inch rear with TruTrac, and rock rails (real beefy rock rails that I modified with four legs and era pinch seam attachments) I do rock crawling a good bit.

What are the pros and cons of long arms. Then there is 4 link, 3 link, and the type that has the upper arms connected to the lower arms.

What about ground clearance, which brands of kits tuck up above the frame rails, which hang down low? (seeing as I do a good deal or rock crawling I know there is a good chance of hitting rocks, I go slow and careful, but things do happen)

suggestion's, reviews, advice wanted.

 

[maxbraketorque]

I think you'll find many people recommend against radius arm ("upper arms connected to lower arms"). People usually site weight transfer issues with radius arm when climbing, and for sure 3/4 link offer a better degree of weight transfer control through tuning of the arm lengths.

My personal pref is 3-link over 4-link. The second upper arm causes minor binding that is unnoticeable with soft bushings but would be more noticeable if using some or all hard bushings.

 

[Black1990jeep]

How big an improvement in articulation will a three or four link long arm give verses the short arms? (Note I have drop brackets for my short arms now) Note I do rock crawling so articulation is needed. also how much will improved articulation help with reducing tip overs on an extreme offset angle with one tire way up on a rock, opposite tire on the ground? That is one of them sinking feeling I do not like.

what of ground clearance of the body side mount of the arms, which brands give the best clearance?

 

[Black1990jeep]

I think you'll find many people recommend against radius arm ("upper arms connected to lower arms"). People usually site weight transfer issues with radius arm when climbing, and for sure 3/4 link offer a better degree of weight transfer control through tuning of the arm lengths.

My personal pref is 3-link over 4-link. The second upper arm causes minor binding that is unnoticeable with soft bushings but would be more noticeable if using some or all hard bushings.

I will likely have a hard bushing like a johnny joint or such on the body side, it looks like standard rubber bushings are usually used on the axle side, is that correct?

 

[Black1990jeep]

I think you'll find many people recommend against radius arm ("upper arms connected to lower arms"). People usually site weight transfer issues with radius arm when climbing, and for sure 3/4 link offer a better degree of weight transfer control through tuning of the arm lengths.

My personal pref is 3-link over 4-link. The second upper arm causes minor binding that is unnoticeable with soft bushings but would be more noticeable if using some or all hard bushings.

Now on the three link, can one simply install a four link set up and remove one of the upper arms to make it into a three link, or are their other differences such as body mounting points involved with a three verses a four link system?

 

[maxbraketorque]

I will likely have a hard bushing like a johnny joint or such on the body side, it looks like standard rubber bushings are usually used on the axle side, is that correct?

That's a common approach. I think some people put hard bushings at both ends. Depends on your intended usage.

Now on the three link, can one simply install a four link set up and remove one of the upper arms to make it into a three link, or are their other differences such as body mounting points involved with a three verses a four link system?

Yes, as far as I'm aware, all 3-link systems are simply sans the non-pumpkin upper arm of a 4-link. You can buy 4-link and try it in both configs.

My thoughts for 3-link are that:

• It would be a good idea for the bolts holding the single upper arm to be more beefy than for a 4-link because there is only one arm handling axle orientation. Surprisingly, I don't think any of the outfits offering 3-link do this. Same bolts whether 3-link or 4-link.
• It might be good to beef up the axle a bit because non-pumpkin side only has one arm attached to it, so its not quite as well supported against twisting forces.

When I converted my radius arm to single y-link on the pumpkin side (a kind of 3-link for radius arm), I installed large diameter bolts on the short arm (and matching bushings), and I had some reinforcement welded onto the long tube of the axle.

 

[Evan03]

I love my 3 link. My lower arms at frame side are 2" below frame. This gives a great control arm angle compared to links that are above the frame making a flat belly.
I do not get hung on link brakets. I have poly bushings on axle with 1.25 heims on frame. Articulation is more than adequate with 12" stroke shocks.

 

[Black1990jeep]

I love my 3 link. My lower arms at frame side are 2" below frame. This gives a great control arm angle compared to links that are above the frame making a flat belly.
I do not get hung on link brakets. I have poly bushings on axle with 1.25 heims on frame. Articulation is more than adequate with 12" stroke shocks.

Hi Evan

What brand of long arms you have, or did you make your own? What is your lift height, and are those 35 inch tires? How much up and down articulation do you have with the 12 inch range shocks? I need to decide if I should lower my rig a bit, but gain more down travel. On rock crawls my rig seems at times a bit high i.e. tippy I am thuinking maybe the low center of gravity approach might be better. Your rig looks very good by the way.

My good friend rob who is currently set up his xj for long arms will be moving to Idaho one day, his son lives there now.

 

[Black1990jeep]

PS I am also at the point of considering trussing the D30, I need to regear anyway as I have 4.11 now. also considering front frame stiffeners at same time. I really need to weld my track bar drop bracket to the frame, so might as well weld it to a stiffened frame.
Tell me, do you all preheat the cast parts of the axle for welding a truss, ie preheat the pumpkin? Or you all just weld away with no preheat? I have a MIG and I have a TIG (but I need to learn TIG technique, am pretty good at MIG now.) I suppose I can preheat with an oxy acetylene torch if need be. suggestions?

 

[Evan03]

I have 5" of up travel and 7" down lift height is roughly 3.5-4". I built the entire set up .
Axle side brackets are raised about 2" to make flatter control arm angle.

I talked with stinky fab and accutune alot to figure out link geometry then accutune valved the coilovers

12" is plenty of shock travel for most rigs.

I did order 14" shocks for the rear a few months ago but they havent showed up yet. Just shocks. 2.5 resivors valved for my rig.

Also orderd 2.5" shock seals shims etc to be able to refresh rebuild. I run 2.5" ressys on my daily driver ford to.


Welding cast sux i think you want to pre heat to 350-400 deg then i use a needle scaller to beat on weld then fire torch up to keep it from cooling to fast.
Ive done alot of pumpkin welding and made just as many cracks.
The needle smaller helps alot seems to be what had made my trusses and stuff more successful.
Research alot dont take my work for it.

 

[Black1990jeep]

What do you all think of the CAVFAB long arm. It has a unique body side upper arm mount, the mount is rotated 90 degrees from the usual orientation. What do you all think of this? See link for it below...

Alpha Series 3-Link Kit - Jeep XJ / MJ

Alpha Series 3 Link was designed to be the best 3 link long arm kit on the market for your Jeep XJ or MJ. Excellent suspension geometry provides for unmatched performance off-road and amazing street characteristics. The best true 3 link long arm upgrade for your Cherokee or Comanche.

cavfab.com

 

[maxbraketorque]

What do you all think of the CAVFAB long arm. It has a unique body side upper arm mount, the mount is rotated 90 degrees from the usual orientation. What do you all think of this? See link for it below...

Alpha Series 3-Link Kit - Jeep XJ / MJ

Alpha Series 3 Link was designed to be the best 3 link long arm kit on the market for your Jeep XJ or MJ. Excellent suspension geometry provides for unmatched performance off-road and amazing street characteristics. The best true 3 link long arm upgrade for your Cherokee or Comanche.

cavfab.com

The primary photo is confusing because it shows two rotated pivot joints. It looks like an upper and lower arm are rotated at the frame-side. Its as if its a Photoshop job done incorrectly.

That aside, I don't see any obvious value to the rotated pivot joint for the frame-side upper arm. If I were to guess, its perhaps easier to install the pivot joint bolt in this orientation.

From my perspective, I would be looking at how the frame side arm housing attaches to the XJ frame. It needs to be a sturdy installation for serious rock crawling. I prefer a bolted installation using many bolts.

 

[Einulfr]

I think it's rotated so that the upper arm mounts could be tucked up as high as possible. You can't run it horizontal as it's above the frame rail and there would be no way to get a bolt through, or they would have to be moved inward slightly to get a nut between the mount and the rail and that would throw off the geometry. Vertical mount isn't a super rare thing, but it's mostly only seen in custom fab and rarely in pre-made kits. Not a big deal so long as downtravel isn't excessive enough to bottom out the johnny joint against its body. I've heard from a couple of guys that it's a really good kit, I just don't like mounts that are integrated into the skid as you have to chock the tires and remove the arms before you can drop the skid and do anything with the transmission or transfer case. That's a really good price for a long arm kit, though.

For the truss, you preheat the pumpkin to 400 first, weld it on, peen the welds immediately afterwards for relief, heat it up again to 400, then wrap it up in a welding blanket to slow cool for about 24 hours. Good time to do C-gussets, also.

 

[Ghost]

After running a 3 link for years. And I mean years. I wish my friend Andy had his kit out when I built mine. I'm biased on this but I love his kit.

XJ/MJ Front 4 Link System

Expect a 30 day build time on all 4 link orders. All new orders will come with our new beam link lowers The 1984-2001 Jeep Cherokee has become A common platform for an affordable off-road vehicle. Sadly the aftermarket has been dragging its feet for years to create an effective tunable platform...

ironman4x4fab.com